/*
 * Copyright 2012 Cisco Systems
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.activiti.karaf.support;

import org.activiti.engine.delegate.VariableScope;
import org.activiti.engine.impl.el.ExpressionManager;
import org.activiti.engine.impl.el.VariableScopeElResolver;
import org.activiti.engine.impl.javax.el.ArrayELResolver;
import org.activiti.engine.impl.javax.el.BeanELResolver;
import org.activiti.engine.impl.javax.el.CompositeELResolver;
import org.activiti.engine.impl.javax.el.ELResolver;
import org.activiti.engine.impl.javax.el.ListELResolver;
import org.activiti.engine.impl.javax.el.MapELResolver;
import org.springframework.context.ApplicationContext;

/**
 * Bpmn Expression manager that handles the EL Resolvers resolving the EL
 * variables to the beans in the application context in osgi bundles -
 * registered through BPMNDeployer spring configuraiton.
 * 
 * @author Srinivasan Chikkala
 * 
 */
public class BpmnExpressionManager extends ExpressionManager {
    private BpmnElResolver osgiELResolver;

    public BpmnExpressionManager() {
        this.osgiELResolver = new BpmnElResolver();
    }

    @Override
    protected ELResolver createElResolver(VariableScope variableScope) {
        CompositeELResolver compositeElResolver = new CompositeELResolver();
        compositeElResolver.add(new VariableScopeElResolver(variableScope));

        // Expose full application-context in expressions
        compositeElResolver.add(this.osgiELResolver);

        compositeElResolver.add(new ArrayELResolver());
        compositeElResolver.add(new ListELResolver());
        compositeElResolver.add(new MapELResolver());
        compositeElResolver.add(new BeanELResolver());
        return compositeElResolver;
    }

    public void addApplicationContext(ApplicationContext appCtx) {
        this.osgiELResolver.addApplicationContext(appCtx);
    }

    public void removeApplicationContext(ApplicationContext appCtx) {
        this.osgiELResolver.removeApplicationContext(appCtx);
    }
}
